Papers by Keyword: Fe-Based Alloys

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Authors: T. Maebashi, Minoru Doi, Takao Kozakai
Abstract: The morphological changes and the coarsening kinetics of B2 particles in A2 matrix in the elastically constrained Fe-16at%Al-18at%Co alloy were investigated by means of transmission electron microscopy (TEM). The mean particle radius increases in proportion to the cube root of ageing time at early stage, then the coarsening of B2 particle decelerate at late stage of aging. And it clarified the decelerated coarsening in Fe based alloy also is related to the change in PSD and is caused by the elastically strained effect.
Authors: Rui Na Ma, An Du, Jian Jun Wu, Xiao Ming Cao
Abstract: In continuous hot dip galvanizing, serving parts working in the molten zinc, such as sink roll, sleeves, etc. tend towards degradation and failure due to corrosion and wear. In this paper, corrosive wear performance of several materials, such as boronized,H13,Co-based alloy and Fe-based alloy coupled with Si3N4 is evaluated with the aid of a self-made test machine of block-column sliding wear. Moreover, the corrosive wear mechanism is analyzed. It has been found that these materials suffered not only considerable wear, but also the corrosion of molten zinc. For boronized layer, the wear is the main reason to cause the failure of work parts under the act of the corrosive wear. For H13, the interaction between corrosion and wear plays a very important role on its failure. For those alloys with bad corrosion resistance such as Co-based alloy and Fe-based alloy, both corrosion of solid solution and wear of intermetallic compound act on their failure at the same time. However, the rate of wear shows no obvious relation to the hardness although wear performance is important. The failure greatly lies on the ratio of the hardness of corrosion products to matrix.
Authors: Conrado R.M. Afonso, Claudemiro Bolfarini, Walter José Botta Filho, Claudio Shyinti Kiminami
Authors: Shi Hai Zhao, Xiu Ming Jiang, Xu Guo Huai, Xiao Wei Fan
Abstract: Laser cladding Fe-based alloy coatings with 0, 3, 6, 9, 12 and 15% Al2O3 xerogel on 45 steel substrates were prepared by 5kWCO2 continuous wave laser. The effect of the content of Al2O3 xerogel on the microstructure, microhardness and wear resistance of the coatings was investigated by scan electron microscope, X-ray diffraction. The results show that the microstructure and properties were different when the content of Al2O3 xerogel changed. The addition of Al2O3 xerogel can enhance the fluidity of molten liquid and refine the microstructure. Adding adequate amount of Al2O3 xerogel to Fe-based alloy can improve the hardness and the wear resistance due to the nano-Al2O3 particles on surfaces and the dispersion strengthening and hardening of nano- Al2O3 particles.
Authors: A.N. Timoshevskii, V.A. Timoshevskii, B.Z. Yanchitsky
Authors: Jian Sheng Wang, Rui Zhu Zhang, Da Kao Yan
Abstract: Electrospark deposition (ESD) is a promising process to produce hard and wear-resisting coating on metallic substrates. Fe–Cr–Ni–Si–Mo–W–B–Co–Al alloy rods were used as electrode to produce coatings onto a high carbon cast steel roll substrate. Different parameters were used and the coatings have an average thickness of~80 μm, which are metallurgically bonded to the substrate. The microstructures of the coating prevail in nanosized grains and amorphous structures. The primary phases of the coating contain C0.055Fe1.945,(Fe,Cr)7C3,Fe7Mo3 and Al0.99Fe0.99Ni0.99. The maximum microhardness value of the coating is about 1837.4 HV. The study reveals that Fe-based ESD coating has a better quality and has a high hardness on the cast steel roll.
Authors: Laura M. Fernandez Diaz, Jing Zhu, Gordon R. Holcomb, Paul D. Jablonski, David E. Alman, S. Sridhar
Abstract: It is known that additions of reactive elements such as Ce, La or Y improve the properties of protective oxide-scales on Ni and Fe based alloys [ - ] by increasing oxide adhesion, decreasing the transient time until a continuous Cr2O3 layer is formed and decreasing the parabolic rate constant. Nevertheless, the precise roles played by these reactive elements to improve scales and the precise mechanisms by which they are incorporated into the scale during the surface treatment processes are unknown. Although they are believed to be associated with transport properties in the scale, it is not clear how this occurs or why it improves oxidation resistance. This project is aimed to gain understanding of the scale evolution in Fe-22 wt.% Cr alloys at 800 oC in dry air during the transient stage after 15 minutes of oxidation. The effect of La (120 and 290 ppm) and Ce (270 and 610 ppm) additions added during melt-stage processing are investigated. The surface oxidation process was imaged in-situ through a Confocal Scanning Laser Microscope (CSLM) and the results were correlated with post-experiment characterization through FEG-SEM and FIB-SEM combined with 3D reconstruction. The roles of rare-earth oxide particles on nucleation of Cr2O3 and blockage of short-circuit diffusion paths in the oxide scale and underlying metal are discussed.
Authors: Conrado R.M. Afonso, Michael J. Kaufman, Claudemiro Bolfarini, Walter José Botta Filho, Claudio Shyinti Kiminami
Authors: Jarmila Degmová, J. Sitek, J. Bednarčík
Abstract: In this paper, a review of recent 57Fe Mössbauer spectroscopy (MS) studies of external influence on the properties of amorphous and nanocrystalline Fe- and Co-based alloys is submitted. Different types of alloys (FeCuNbZr, FeCuNbSiB, FeCoCuNbB, CoFeZrB and CoFeSiB) in the form of original amorphous and nanocrystalline ribbons were subjected to different external factors: different annealing atmospheres, mechanical stress (for example influence of ball-milling) and tensile stress. It will be shown that the Mössbauer spectrometry is a suitable tool for such studies because the measured spectral parameters are very sensitive to the changes in the vicinity of the probe 57Fe-nuclei and thus, this technique provides a wide variety of information about structural and magnetic behavior of Fe-containing materials.
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